Conventionally, there has been proposed a technique for improving an energy efficiency when a valve body opens and closes an opening of a compressor.
For example, in a sealed compressor disclosed in Patent Literature 1, a discharge valve opens and closes a passage penetrating a compression chamber and a discharge chamber. The discharge valve is provided with an elastic reed which is bent to bias the discharge valve in a direction to open the discharge valve. A valve spring is positioned on the discharge valve. This valve spring limits an opening degree of the discharge valve by its elastic force. This causes a pressure in the compression chamber to be lower than a pressure in the discharge chamber. When this differential pressure exceeds the elastic force of the elastic reed, the discharge valve closes the passage. On the other hand, when the pressure in the compression chamber exceeds the pressure in the discharge chamber, the discharge valve is biased by the elastic reed and opens the passage, so that a working fluid flows from the compression chamber into the discharge chamber.